In 2012 Lays seemed to issue this limited edition flavor out of the blue: Sweet Onion.
I wasn't too enamored with the idea, and I learned that I felt the same about the taste.
With such a simple flavor base, as I expected, Lays calls upon a few other ingredients to play a support role. Each bite begins strong with onion, which isn't unpleasant, but a formidable sweetness arises in the form of sugar. Perhaps Lays worked a bit too hard to drive home the "sweet" onion character, as this combination doesn't seem very natural. Midway through each bite and on the swallow, there is a strong herbal note of thyme, and perhaps even parsley and oregano. The thyme note is strong, and I feel it's misplaced. This strong herbal punch reminds me a bit of Lay's Chicken and Waffles. Imagine a bunch of potatoes drowned in a run-of-the-mill sweet onion salad dressing, and you've got the picture.
I'm a potato chip freak, and if someone gave me another bag of these, it would gather dust on the shelf. We're barely in the 2-NOM range, here.
Lay's Sweet Onion:

Original Lay's(for comparison):
